Lockwasher



g- 1965 o. J. POUPITCH 3,199,565

LOCKWASHER Filed Feb. 11, 1963 ,Z INVENTOR.

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United States Patent 3,199,565 LOCKWASHER Gugijesa .Inles Poupiteh, Etasea, Iih, assignor to Illinois Tool Works Inc., Chicago, 115., a corporation of Delaware Filed Feb. 11, 1963, Ser. No. 257,550 Claims. (Cl. 151-35) The present invention relates generally to lockwashers and more particularly to annular type sheet metal lock- Washers wherein at least a portion of material normally discarded as scrap or waste stock is retained for increasing the locking efiiciency of the washer.

It is of extremely important economic significance in the manufacture of lockwashers, to reduce as far as possible the amount of waste material. To this end the present invention contemplates a lockwasher which may be formed from strip sheet metal stock in such a manner as to reduw scrap to a minimum.

Also, the invention contemplates the use of a portion of the sheet metal stock which has heretofore been discarded as scrap material for effectively increasing the locking etficiency of the finally completed lockwasher member. Thus for example, sheet metal in the form of a disc is usually punched from the center of the annular washer stock and discarded as waste material. The present invention contemplates using a portion of this scrap stock to function in association with the washer body and locking teeth so as to improve the locking efficiency of the washer.

The foregoing and other objects and advantages will be more apparent from the following detailed description, wherein:

FIG. 1 discloses a strip of sheet metal stock embodying lockwashers prior to the separation of the lockwashers from said strip;

FIG. 2 is a plan view of a lockwasher after it has been separated from the strip of FIG. 1 and before the abutment members along the inner margin have been folded into adjacent superimposed relation with the washer body;

FIG. 3 is a view similar to FIG. 2 showing the position of the above mentioned abutments formed integral with and extending from the inner margin of the washer body after said abutments have been folded or shifted into superimposing relation with the Washer body; and

FIG. 4 is a central vertical sectional view of the lockwasher of FIG. 3 shown in operative association with a rotary threaded clamping member or nut.

Referring now to the drawing more in detail, wherein like numerals have been employed to designate similar parts throughout the various figures, it will be seen that one embodiment of a lockwasher contemplated by the present invention is designated generally by the numeral 10. This lockwasher includes diametrically disposed annular body portions 12 having radial prongs 14 formed integral with and extending from the outer margin thereof. Each of the prongs 14 is twisted or deflected to provide washer teeth 14:: normally projecting beyond the bounding planes of the body portions 12. Positioned intermediate the body portions 12 are body portions 12a of increased radial extent or width. Each extremity of these body portions 12a is preferably deflected so as to provide additional teeth 14a as shown in the drawing.

Formed integral with the inner margins of the body portions 12a of the increased width, are oppositely disposed prongs or tabs 16. In the manufacture of the washers these tabs 16 initially occupy the position shown in FIGS. 1 and 2, namely in a coplanar relationship with their respective body portions 12a. Thus, when the central aperture 17 of the lockw-asher is formed a portion of the vmaterial usually discarded as waste or scrap is retained in the form of the tabs 16. Before the lockwasher ice is heat treated so as to impart the proper degree of hardness thereto, the tabs 16 are folded over the body portions 12a so as to occupy the position shown in FIGS. 3 and 4. In this position the tabs traverse and adjacently superimpose one side of the intermediate body portions or sections 12a whereby to provide a plurality of abutments for counter-acting tendency for the locking teeth 14a to become flattened when the washer is finally clamped in position by a rotary clamping member or nut 18 on one side against the surface of a workpiece 2% on the opposite side. It will be noted that each of the abutment members or tabs 16 incorporate relatively sharp corners 16a. In certain instances these corners or teeth 16a cooperate to increase the locking efficiency of the washer.

The above described lockwashers may be for-med from a strip of sheet metal stock 22 as illustrated in FIG. 1.

The structural features of the lockwashers are such as to make it possible to blank or stamp the lockwasher by employing a substantially scrapless method. .That is to say, the arrangement of the body portions, tabs 16, and locking prongs 14, make it possible to form the washers from a strip of appropriate material in such a manner as to effect a substantial reduction in the amountof waste or scrap material. It will be noted from FIG. 1 that each washer is connected to the other by oppositely twisted locking prongs readily fractura-ble to provide complete or individual washers. The invention contemplates separation of the washer elements either before or after heat treatment. If the separation is to be produced after heat treatment, the tabs 16 are folded to the position illustrated in FIGS. 3 and 4 at the time the washers in strip form are being stamped and the sheet stock is unhardened. On the other hand, if the washers are separated before heat treatment, the tabs 16 may be folded into superimposed relationship with the body portions or sections 12a either while in strip form or after being separated from the strip but before the sheet metal is subjected to heat treatment.

From the foregoing it will be apparent that the present invention contemplates a lockwasher of improved practical construction, assuring increased locking aggressiveness due to the presence of the abutments 15, which serve to prevent the locking teeth from being completely flattened. In other words, because of the presence of the abutments or tabs 16, the prongs 14 can only be untwisted within certain limits, thus providing continuous yieldable locking tooth resistance to unauthorized loosening of a threaded clamping member tightened against the washer. Reducing the waste or scrap material as described above contributes materially in lowering the cost of manufacture.

Obviously the illustrations in the drawing are representative of only one embodiment of the invention. Other modifications and changes are contemplated which come within the scope of the appended claims.

The invention is claimed as follows:

1. A sheet metal lockwasher including an annular body, a plurality of locking prongs supported by and extending from the outer margin of a limited circumferential first section of said body, a plurality of locking prongs supported by and extending from the outer margin of a limited circumferential second section of said body, said prongs being deflected so as to present locking teeth projecting axially beyond the bounding planes of said prong supporting sections of said body, intermediate circumferential sections of said body extending between and having substantially greater radial width than said first and second body sections and a circumferential extent substantially greater than the width of a prong, and tabs extending from and formed integral with the inner margin of each of said intermediate body sections, said tabs being folded along a line adjacent and substantially parallel to said margin and traversing and adjacently superimposing one side of said intermediate body sections whereby to provide a plurality of abutments for counteracting tendency for said locking teeth to become flattened when the washer is finally tightened against a workpiece said intermediate body sections of greater radial width exceed in circumferential extent the circumferential width of said tabs and present exposed extremities on opposite sides of said tabs.

2. A sheet metal lockwasher as set forth in claim 1, wherein the intermediate body sections and associated abutment tabs are positioned diametrically opposite each other.

3. A sheet metal lockwasher as set forth in claim 1, wherein the opposite circumferential extremities of said intermediate body sections are deflected to provide looking teeth in addition to the teeth of the locking prongs.

4. A sheet metal lockwasher as set forth in claim 1, wherein the free extremities of said abutment tabs provide acute work engaging teeth.

5. An article of manufacture comprising a strip of metal lockwashers of which adjacent ones are secured to each other by readily fracturable, abutting, oppositely twisted washer prongs extending from and symmetrically disposed with respect to the outer margin of arcuate body sections of given radial width, said arcuate sections being of a circumferential extent sufiicient to support a plurality of external radially extending locking prongs, and positioned diametrically opposite each other, diametrically positioned body sections intermediate the first mentioned body sections and having radially disposed tab members integral with and extending radially inwardly from the inner margins of said intermediate sections with the tab members adapted to be folded along the inner margin to adjacently superimpose the intermediate body sections, said intermediate body sections having a greater radial width than the first mentioned body sections and a circumferential extent substantially greater than the width of a washer prong, said intermediate body sections of ad; jacent washers extending transversely of the strip and separated by relatively narrow elongated recesses whereby to reduce the amount of waste sheet metal stock of said strip.

References Cited by the Examiner UNITED STATES PATENTS 2,234,194 3/41 Poupitch 151--35 2,321,155 6/43 Poupitch 15l35 2,636,253 4/53 Rees 1073 2,842,181 7/58 Machac l5l35 CARL W. TOMLIN, Primary Examiner.

EDWARD C. ALLEN, Examiner. 

1. A SHEET METAL LOCKWASHER INCLUDING AN ANNULAR BODY, A PLURALITY OF LOCKING PRONGS SUPPORTED BY AND EXTENDING FROM THE OUTER MARGIN OF A LIMITED CIRCUMFERENTIAL FIRST SECTION OF SAID BODY, A PLURALITY OF LOCKING PRONGS SUPPORTED BY AND EXTENDING FROM THE OUTER MARGIN OF A LIMITED CIRCUMFERENTIAL SECOND SECTION OF SAID BODY, SAID PRONGS BEING DEFLECTED SO AS TO PRESENT LOCKING TEETH PROJECTING AXIALLY BEYOND THE BOUNDING PLANES OF SAID RPONG SUPPORTING SECTIONS OF SAID BODY, INTERMEDIATE CIRCUMFERENTIAL SECTIONS OF SAID BODY EXTENDING BETWEEN AND HAVING SUBSTANTIALLY GREATER RADIAL WIDTH THAN SAID FIRST AND SECOND BODY SECTIONS AND A CIRCUMFERENTIAL EXTENT SUBSTANTIALLY GREATER THAN THE WIDTH OF A PRONG, AND TABS EXTENDING FROM AND FORMED INTEGRAL WITH THE INNER MARGIN OF EACH OF SAID INTERMEDIATE BODY SECTIONS, SAID TABS BEING FOLDED ALONG A LINE ADJACENT AND SUBSTANTIALLY PARALLEL TO SAID MARGIN AND TRAVERSING AND ADJACENTLY SUPERIMPOSING ONE SIDE OF SAID INTERMEDIATE BODY SECTIONS WHEREBY TO PROVIDE A PLURALITY OF ABUTMENTS FOR COUNTERACTING TENDENCY FOR SAID LOCKING TEETH TO BECOME FLATTENED WHEN THE WASHER IS FINALLY TIGHTENED AGAINST A WORKPIECE SAID INTERMEDIATE BODY SECTIONS OF GREATER RADIAL WIDTH EXCEED IN CIRCUMFERENTIAL EXTENT THE CIRCUMFERENTIAL WIDTH OF SAID TABS AND PRESENT EXPOSED EXTREMITIES ON OPPOSITE SIDES OF SAID TABS. 